Plate-lifting device



May 8, 1962 J. D. NOBLE ETAL 3,03

PLATE-LIFTING DEVICE 8 Sheets-Sheet 1 Filed Feb. 10, 1958 INVENTORS JACK 0. NOBLE GEORGE WAYNE BENTLEY E064 6'. ICE

ATTORNEY May 8, 1962 J. D. NOBLE ETAL PLATE-LIFTING DEVICE 8 Sheets-Sheet 4 Filed Feb. 10, 1958 GEORGE WAYNE BENTLEY B EigA/i 6'.fi/ E ATTORNEY- May 8, 1962 J. D. NOBLE ETAL PLATE-LIFTING DEVICE 8 Sheets-Sheet 5 Filed Feb. 10, 1958 jg. c9.

n s m n w m m. flw BEBE R WLE 0 IBN/ T O R T A A W0 DE 6R 4 mmr a M655 iii aw w w H W 9 0 8 5 2 7 8 -v w E 5 7 7 6 m J 7' May 8, 1962 J. D. NOBLE ETAL 3,033,381

PLATE-LIFTING DEVICE Filed Feb. 10, 1958 8 Sheets-Sheet 6 "w INVENTOR.

JACK D- NOBLE GEORGE WAY/VEEE/VTLEY YEDGAI? 0. ICE

Q W M ATTORNEY May 8, 1962 J. D. NOBLE ETAL PLATE-LIFTING DEVICE 8 Sheets-Sheet '7 Filed Feb. 10, 1958 INVENTORS JACK 0- NOBLE GEORGE WAYNE BENTLEY E AR 0. ICE 2 ATTORNEY.

' atent hhce 3,033,381 lilLATE-LEFTENG DEVEQE Jack D. Noble, 3649 Happy Valley Road, Lafayette, Calif.; George W. Bentley, 36 Orchard Road, Orinda, Calif; and Edgar C. Rice, 1435 Edward Court, Lafayette, Qalif.

Filed Feb. 10, 1958, Ser. No. 714,121 13 @laims. (Cl. 212-129) This invention relates to improvements in plate-lifting devices, especially those of the type employing vacuum 'or suction cups or electromagnets. It also relates to an improved plate-lifting attachment for use with overhead cranes.

Many industrial plants have overhead cranes with a bridge that moves along widely spaced runway rails and a trolley that moves back and forth on the bridge carrying a cable hoist for raising and lowering a hook. In some cranes movement of the bridge, trolley, and hoist are controlled from the floor by a control cable suspended from the trolley; in other cranes an operator controls them from a cage, usually located on one end of the bridge. In any event, the hook can be used to lift and transport many things from one part of the factory to another. However, a hook is not able to lift one sheet at a time of steel plate (or other sheet material) and move it without first applying straps, chains, or other tackle to the plate, so that the operation becomes very time-consuming and inefficient. Heretofore specialized equipment, completely separate from the overhead crane, has been required for rapid movement of plates from one part of the factory to another.

The .present/ invention provides a detachable plate-lifting attachment that adapts overhead cranes to rapid plate lifting and carrying. The use of this attachment greatly increases the versatility of the cranes. Moreover, it is quickly attached and detached; so the crane can still be used as usual when the plate-lifter attachment is taken off.

A problem that had to be surmounted before this invention could-be considered practical was how to restrain the hoist cable from rotating or swinging like a pendulum. Otherwise, when a piece of steel plate was supported solely by the hoist cable, both the plate and the vacuumcup or electromagnetic plate-lifting structure would tend to swing back and forth or to rotate relative to the trolley, turningback and forth during carrying. Such movement is intolerable when moving heavy steel plate around, especially with vacuum or magnetic equipment. The plate is quite likely to strike a worker or damage a machine, and even if it doesnt, it is difficult to stack plate straight or to feed it to a machine in the'face of constant swinging or turning, first in one direction and then in the other. The present invention has solved this problem by providing a novel stabilizer'readily attached to and readily detachable from the trolley. When attached, the stabilizer serves vto prevent swinging,.rotation, turning, twisting, and swaying, but the stabilizer itself carries no load during operation. All the weight of lifting is exerted through the hook and the cable.

As implied above, the objects of this invention include the provision of a plate-lifting attachment for overhead cranes, the stabilization of the plate-lifting attachment relative to the trolley, rapidity of application and detachment of the plate-lifter to overhead cranes, and rapidity and simplicity in coupling and uncoupling the stabilizing apparatus.

Another related object is the provision of special safety features in connection with the stabilizing apparatus.

Another object of the invention is to make it possible for'the crane operator, whether at ground level or in a cage, to control the whole plate-lifting apparatus, just Patented May S, 1962 as it is alreadypossible for him to control the overhead crane.

Other objects and advantages ofthe invention will ap pear from the following description of some preferred forms thereof.

In the drawings:

FIG. 1 is a top plan view of an overhead crane system incorporating a plate-lifting attachment embodying the principles of the present invention.

FIG. 2 is a perspective View of a portion of the crane of FIG. 1 showing the trolley and hoist supporting the attachment.

FIG. 3 is a view in side elevation of a trolley and a portion of the bridge of the overhead crane of FIG. 1. The middle portion of the hoist cable and of the stabilizer and the ends of the bridge are broken in order to conserve space.

FIG. 4 is a view in front elevation of the assembly of FIG. 3 with the motor compressor, suction pump, and some other parts being removed from a vacuum-type plate-handler that in this instance comprises the bottom portion of the apparatus, in order to show other parts more clearly. The bridge and the trolley rails are shown in section, and the cables and stabilizer are broken as before.

FIG. 5 is a bottom plan view of a portion of the trolley showing the attachment thereto of the vertical supporting members, taken along the line 55 in FIG. 6.

FIG. 6 is an enlarged view in front elevation and partly in section of the stabilizer and related portions of the device, with some parts broken in order to conserve space. The stabilizer and plate-lifting attachment are shown in detached position preparatory to being joined to the vertical members that depend from the trolley of the overhead crane, most of the plate-lifting frame being broken off.

FIG. 7 is a view in side elevation and partly in section of the assembly shown in 'FIG. 6.

FIG. 8 is a further enlarged top plan view, partly in section, of the stabilizing apparatus. 7

FIG. 9 is a fragmentary view in elevation and in sec- .tion on the scale of FIG. 8 of one juncture between a stabilizer tube and the bayonet mount therefor, shown in installed position.

FIG. 10 is a'view in front elevation of the lower por- 'tion of a modified form of lifting attachment employing electromagnets instead of suction cups. As in FIG. 4, the. compressor and some other parts have been omitted for the sake of clarity.

FIG. 11 is ,a view similar to the upper partof FIG. 4 but showing a modified form of the invention wherein the hoist is mounted stationary with respect to the bridge instead of being on a movable trolley.

FIG. 12 is a bottom plan view similar to FIG. 5 of a modified form of the invention wherein there are three :depending vertical members, three stabilizer tubes being employedin conjunction with them. 7

FIG. 13 is a fragmentary view in side elevation and partly in section, somewhat similar to FIG. 9, showing ,a modified form of latch arrangement with the latchin its closed or locked position.

FIG. 14 is a view similar to FIG. 13 with additional parts in section and with the latch shown in its unlocked position.

FIG. 16 is a somewhat enlarged view in section taken along the line 16-16 in FIG. 15.

FIG. 17 is a fragmentary view in elevation of a part of modified form of one-leg stabilizer arrangement, incoporating I-beams that slide relatively to each other instead of telescoping tubes.

FIG. 18 is a view in section taken along line 1818 in FIG. 17.

A Typical Overhead Crane Described While overhead cranes are well known in the art, FIGS. 1-4 disclose the basic structure of a typical such crane 20. A bridge 21 is mounted on wheels 22 for movement along a pair of widely spaced-apart runways 23, when driven by a power device 24. The runways 23 typically rest directly on or form part of structural beams 25 located high above the floor 26 of the building. The bridge 21 itself comprises a pair of structural beams 27, joined adjacent their ends only and supporting a pair of rails 28 on their upper surfaces.

A trolley 30 has flanged wheels 31 that run back and forth on the rails 28, powered by an electric motor 32, and chain drive 33. The trolley 30 supports a hoist 35 comprising a drum 36, cable 37, block 38, and cable-ended anchor 39. The block 38 supports a hook 40, preferably by a pivot pin 41, for engaging and carrying a load. A reversible motor 42 on the trolley 30 rotates the drum 36 through reduction gears 43 and 44. By moving the trolley 30 on the bridge 21 and the bridge 21 on the runways 23, any point in the area between the runways 23 can be reached, and the hoist 35 makes it possible to reach any height between the runways 23 and the floor 26 (or even lower, if there are openings in the floor 26). Control may be obtained at floor level by a control cable 45 depending from the trolley 36 or by a control board in an operators cage (not shown), usually located at one end of the bridge 21 but sometimes on or adjacent the trolley 30.

Of course, some overhead cranes, like the crane 230 in FIG. 11, have no trolleys but have a fixed hoist 231 on their bridge 232. Other cranes have turntables on their trolleys. The present invention is also applicable to these and other types of cranes.

The Stabilizer and Its Attachment (FIGS. 2-9) The present invention makes it possible to adapt this conventional overhead crane 20 to important new uses of which it formerly was incapable. To begin with, one or more downwardly extending vertical structural members are regidly secured to the trolley 30, or, in the crane 230, to the bridge 231. Preferably, two such members and 51 are secured by welding a pair of angle irons 52 to the bottom of the trolley 30 and welding a pair of channel irons 53 across the angle irons 52 (see FIG. 5). The upper portion of each member 50 and 51 may comprise a cylindrical pipe 54 welded to one channel iron 53 and further supported by a pair of braces 55 that are welded both to the pipe 54 and to the channel iron 53.

To the lower end of the pipe 54 is secured a bayonettype coupler 56. Each coupler 56 has a cylindrical shank 57, a latch-engaging recess 58, a lower cylindrical portion 59 (on the member 50), or 69 (on the member 51), and a tapered lower end 61. The recess 58 in each instance has a lower cylindrical portion 62 (see FIG. 9) extending upwardly from a locking shoulder 63, and an upper frustoconical portion 64 leading to the shank 57. Preferably, as shown, the lower cylindrical portion 59 of the member 50 is somewhat longer than the corresponding portion of the other member 51 for a reason which will appear presently.

The bayonet couplers 56 may be welded directly to the lower ends of the pipes 54, but a preferable juncture is provided by the structure shown in FIGS. 4-6. A flange 65 is welded to the lower end of the pipe 54, and an interiorly threaded coupler sleeve 66 is welded to the flange 65. The upper end 67 of the shank 57 is threaded to screw inside the sleeve 66, and an hexagonal lock nut 68 is also threaded on the end 67 against the sleeve 66. This makes the couplers 56 removable by taking off the locknuts 68 and then unthreading them from their sleeves 66. In any event, the cable 37 hangs midway between the two vertical members 50 and 51. The members 50 and 51 being relatively short, do not ordinarily interfere with the normal operation of the crane 20, and if they are too long, the couplers 56 can be removed, leaving the pipes 54 the only portion permanently installed on the trolley 39. All the rest of the attachment is readily removable or attachable.

The present invention employs the two vertical members 50 and 51 as the supports for an upper stabilizing assembly 79. As shown in FIGS. 2-4 and 5-8, a horizontal U- shaped frame 71 joins two long vertical guide or extension tubes 72 and 73 adjacent their upper ends. A convenient distance above and near the U-shaped frame 71, the tubes 72 and 73 are provided with slotted openings 74 through which a movable locking dog or latch 75 extends. A bracket 76 has an opening 77 in line with the latch opening 74, and a second bracket 78 has another opening 79 in line with the openings 74 and 77, both brackets 76 and 78 being supported by the frame 71 at spaced distances from each other and from the latch opening 74. The latch 75 is guided by the aligned openings 74 and 77 and has a stem 80 extending through the bracket 78 and terminating in an eye 81. A spring 82 between the latch 75 and the bracket 78 urges the latch 75 to a normally closed radially inner position. A cord 83 attached to each eye 81 passes over pulleys 84; one cord 83 is joined to the other cord 83, one or both of which pass thence to the lower end of the device (or other control point) so that the coupling and uncoupling can be manipulated from below or from another control point. The face 85 of the latch 75 is sloped or cammed, extending in further at its lower end.

When the tube 72 is aligned with the longer bayonet coupler 50 and the tapered end 61 is inserted part way into the tube 72, the frame 71 may be rotated sideways until the second coupler 51 is also properly aligned and its tapered end 61 inserted into the tube 73. The tapered, conical lower ends 61 force the latch 75 outwardly, but when the recesses 58 are reached, the springs 82 push the latches 75 in, to lock them above the shoulder 63 just above the lower cylindrical portions 59 and 60. The upper conical tapered portions 64 provide sufi'icient lost motion so that if the operator does not stop the relative movement between the tubes 72, 73 and the vertical members 50, 51 as soon as the latches 75 are engaged, he will not damage any parts, for the latches 75 will slide up the portions 63, later sliding back to their proper position. Upper flanges 86 on the tubes 72 and 73 provide a guide to the operator in this coupling operation and also provide a definite stop by engaging the lock nuts 68.

There are also lower flanges 87 on the lower ends of the tubes 72 and 73, and these help hold lower sleeve bearings 88 in place. Upper sleeve bearings 89 may be secured in place a few feet above the lower bearings 88, as by set screws 89. Modified forms of stabilizers will be discussed later (FIGS. 12 et seq., for example).

The Lower Frame 90 and Its Connection to the Crane and Stabilizer The entire auxiliary lifting attachment is supported by a frame 90 which, in the structure that will first be discussed, has three upwardly extending, in-line vertical standards 91, 92, and 93. The standards 92 and 93 may extend up from an upper horizontal frame member 94 that is supported by the central standard 91. The standard 91 is connected to a lower horizontal frame member or base frame 95. (See FIGS. 6 and 7.) The upper end end of the central standard 91 is provided with an eye 96 and a bar 97 which is grasped by the hook 40 and constitutes the sole support for the load carried by the frame 90.

The standards 92 and 93 extend a substantial distance above the standard 91 and preferably constitute cylindrical pipes. They move up and down in the tubes 72 and '73, contacting only the sleeve bearings 83 and 89. Preferably, there is no cap preventing retraction of the standards 92 and 93 from the tubes 72 and 73 because that is not necessary, and sometimes disassembly may be desirable. In normal use they are never moved far enough in opposite directions to come apart. They serve only a guiding and stabilizing function and do no lifting. When the hook 4% is disengaged from the bar 97, the cord (3 is-also pulled, and the stabilizer 79 is detached from the members 5t) and 51, staying with the frame 99 both when used and when not used. During assembly, the sole lifting and support of the attachment is through a bar Q7, hook 4t and cable 37, which are always made capable of lifting much heavier objects than the attachment of this invention, even when it is loaded with steel plate. The hoist determines the height of the base frame above ground level and carries everything, while stability and protection from rotational movement is provided by the guide tubes 72, 73 and the tubes 92, 93. Lifting is then truly vertical, and the crane trolley 33 accomplishes all the lateral and lengthwise movement from one part of the factory to another.

The Vacuum Lift Device (FIGS. 2, 3, 4, 7 and 9) T het lower horizontal frame member or base frame 95 may support a vacuum lift device 100, electromagnetic lift device 220 (FIG. 10), or other type of lift device, preferably of the contact type. (Contact lift means includes both suction cups and electromagnets.) The base frame 95 preferably comprises a pair of channels 101 and 162 (FIG. 7) arranged on their sides facing each other and a series of brackets 103 holding them together in spacedpart relation (see FIG. 4). As shown in FIGS. 2 and 3, the frame 95 preferably supports a motor compressor 1G4 and a compressed air tank 105, preferably by means of extension platform 1% and supporting bracket 157. Through some of the brackets 103 there are holes that receive and guide the vertical movement of stem members 108, at the lower end of which are vacuum cup assemblies or electromagnets 221. The vacuum lift device will be discussed first.

The suction cup assemblies 110 are substantially as shown in application Serial No. 635,172 filed January 22, 1957 Each suction cup assembly 110 includes at its lower end a fiat steel disc 111 with an annular rubber cup member 112 extending down from around its outer periphery. Each steel disc 111 may be secured to a universal joint 113, which, in turn, is connected to a stem 198. The vacuum cup assemblies .111) are mounted with a spring 114 bearing between the disc 111 and a bracket 193 on the lower side of the frame 95. This makes it possible for the cup 11% to engage a plate to be lifted and to come into sealing contact with it and then for the frame 95 to move down further relatively to the suction cup 110 without depressing the suction cup 119 to any great extent but merely compressing the spring 114. This spring mounting in connection with the universal joint 113 assures engagement of the cup 110 with the plate 120, even if the plate 120 should be bent or otherwise not perfectly fiat, and it does allow for an uncritical amount of movement between the litfing frame 95 and the suction cups 110 without any harm to the device.

A flexible conduit 116 leads from each cup 110 to a main transverse conduit 117, the flexible conduit 116 permitting relative movement between the main conduit 1'17 and the cup 110 when the spring 114 is compressed. The valve 115 may be preset to a desired suction value or can be closed off when fewer cups 110 are to be used, so that suction will be exerted only in the ones used. For the sake of adaptability, etc., the valve 115 may be manually operable for individually closing off the conduit 116 and for regulating the pressure at this point to any desired amount. The valve 115 is connected so that, when open, it is either a vacuum line or a pressure line. Vacuum is obtained by connecting the valve across the compressor 194 so that it is pumping from the cup 114), while the pressure is obtained by connecting it across the output side of the compressor "104 so that it is pumping air to the cup 110.

A vacuum switch may be provided in the line 117. The switch may be a well-known type of mercury switch or any other suitable vacuum-operated switch that does not close until a predetermined vacuum is obtained in the line. Until such vacuum is obtained, and the switch is closed, the lifting apparatus cannot be operated. Further explanation of this feature appears in the divisional application, Serial Number 4,167, filed December 21, 1959.

So far as the vacuum lift arrangement 10%} is concerned, the operator moves the crane trolley 30 in the normal way and uses the hoist 35 to cause the suction cups 110 to drop down on top of a plate 120. Normally the pump 1M is kept going all the time, and when the cups '11 0 make contact with the plate 120, a vacuum begins to build up in the line 117. When the pump 194 is able to achieve the predetermined degreeof vacuum, the vacuum switch is thrown. Then by pressing a conventional control button for the hoist 35, the operator can cause the plate 124 to be lifted.

The vacuum-cup arrangement is sufficient to lift and carry the plates 12% from one place to another, and they provide the main lift. However, ti has been found by. experience that vacuum-lift systems are not foolproof, and safety precautions must be taken or else the operation of moving heavy plate will be dangerous. -F or that reason, the present invention provides a plurality of pairs of mechanical safety hooks or grapplers 121.

The grapplers 121 are pneumatically operated in pairs by an air cylinder 122 supported transversely across the frame 95 for each grappler 121. A piston moves in each cylinder 122 at the end of an elongated rod 126, which is connected to a small trolley truck 13%. Conduits 128 and connect the cylinder 122 to the compressor 104.

The truck 130 has wheels 131 mounted thereon for movement along rails provided by an l-beam 133. The I-beam 133 is supported below and transverse to the frame 95 by a bracket 134, and each I-beam 133 supports two trucks 139, one on each side of the frame 95.

The grapplers 121 work in pairs on opposite sides of the plate 120, and each one is moved in by its pneumatic cylinder 122 until it engages the plate120, where it is held, for the pneumatic .force is not so strong as to flex or bend stiff plate. When the grapple is brought into engagement, it necessarily prevents the plate 120 from dropping.

The brackets 134 provide a lost-motion connection between the frame 95 and the I-beam 133; if the safety grap ple should touch the floor, the frame 95 and suction cups 11% can continue to move down, or if the safety grapple should strike another stack of plates, the suction cups 110 can continue to move down.

The pneumatic system for the safety grapple and the structural details of the grapple are fully described in application Serial Number 4,167 .filed December 21, 1959.

By moving the switch 196 to its C position, the motor 42 is operated to cause the hoist 35 to lower the cable 37 and the hook 4t and therefore to lower the frame 95 with its suction cups 119. During this lowering a cable unwinds from a reel 152 having a rewind spring. Lowering is continued until the cups 110 engage the plate 120 and until the springs 114 are somewhat compressed. If the grapplers 121 touch the floor, the lost-motion con- .nection provided by the bracket 134 permits additional movement of the cups 110. The compressor 104 is being operated to suck in air through the cups 110. The cups 113 engage the plate 120 and are evacuated. Whenthe 7 proper pressure level is reached, the vacuum switch is closed.

Then the operator knows that it is safe to lift the plate 120. He then moves the switch 196 to its A position where the motor 42 winds the hoist 35 and lifts the hook 40, and the vacuum cups 110 lift the plate 20. Meanwhile, the spring-loaded reel 152 rewinds the cable 159 as fast as it slackens. When the cable 150 has reeled in a predetermined amount, air is sent under pressure to the cylinders 122, so that the grapplers 121 will be moved toward each other and serve their safety function. When each grappler 121 engages the plate 120, it stops moving. The plate 120 may then be lifted higher and carried by the trolley 30 to the desired point. during lifting and lowering, the cable 37 is the sole lifting member, but the tubes 72, 73 and 92, 93 guide and stabilize, preventing sway or rotation, the tubes 92 and 93 moving up in the tubes '72, 73 as the hoist 35 raises the hook 40 and moving down as the hook 40 is lowered.

When it is desired to release the plate 120, the operator manually presses the release button 174. This causes the grapplers 121 to move apart from each other. At the same time air is sent under pressure into the lines 117 and cups 110, breaking the vacuum, and dropping the plate 120 from the cups 11-1.. The crane 20 may then be pcratcd to lift another plate, by repeating the cycle.

Operation of Installing 0r Delaching Plate-Lifting Attachment when needed and taken off when the crane is to be used otherwise. The attachment is kept and stored as a unit, including the vacuum lift device 100, the attachment frame 90, and the stabilizer 70. When the device is to be used, the trolley is moved to a position vertically above the stored attachment, and the book is lowered to reach into the eye 96 and is then raised to engage the bar 97. The hoist 35 is then operated to raise the hook 40, carrying with it the frame 99 and the stabilizer 70. At this time the stabilizer 70 usually rests with its lower flanges 87 on the horizontal frame member 94. The assembly is lifted until the upper end of the stabilizer tube 72 approaches the tapered lower end 61 of the vertical member and then is lifted slowly and carefully so as to guide the lower end 61 into the tube 72. When this has been done, the book 40 is raised a few inches further until the lower end 61 of the member 51 is just above the other tube 73. The members 73 and 51 are aligned, and then the hoist 35 is again operated to raise the stabilizer 70. As it goes up, the latches 75 in the tubes 72 and 73 ride up the conical face of the lower end 61 and over the cylindrical faces of the members 59 and 69 until they reach the recess 53. At that point the spring 78 pushes the latches 75 inwardly to lock them above the shoulder 63. If the crane operator does not stop the hoist 35 at once, it lifts the stabilizer 70 up slightly further, riding either on the cylindrical face 58 or up the conical face 64, the flanges 86 and 64 providing a stop, if necessary, or at least a visual guide by which the operator can tell the relative positions of the elements. He may then lower the hoist 35, and upon doing so, the latch will invariably engage the shoulder 63 so that the tubes 72 and 73 will not move down. From now on the operation of lowering the hook 40 will lower the standard 91 relative to the stabilizer 70, while the standards 92 and 93 slide up and down in the tubes 72 and 73 to guide the standard 91 and to prevent relative rotation between the trolley 39 and the vacuum lift device 100.

When it is desired to remove the attachment, the op erator preferably raises the hook 40 until the flanges 87 rest on the cross member 94 and then carefully lowers the hook 40 while pulling on the cords 83 to retract the latches 75. The stabilizer 79 can thus be uncoupled from the vertical members 50 and 51. Then he lowers the hook 40 until the lower end of the attachment rests on the factory floor, preferably adjacent a suitable supporting structural member against which the device can be leaned. However, if desired, it can be laid out on the floor. He then uncouples the hook 40 from the member 97 and is free to use the crane for its normal uses.

An Electromagnetic Type of Lifting Device 220 (FIG. 10

As stated earlier, this invention is not limited to use with vacuum-cup types of lifting devices, useful and novel as it is therewith. The invention is applicable to any lifting device having the same general problems. The stabilizer system and safety grapple are, for example, just as useful with the electromagnetic lifter 220 illustrated in FIG. 10. There the frame supports the l-beams 133 and safety grapples 121 just as before for pneumatic operation through the cylinders 122. The only substantial change is that a series of electromagnets 221 are supported on the stems 108, instead of the suction cups 110. The electromagnets 221 are spring mounted, as were the cups 110, and indeed the principal difference is the use of magnetic force and direct electrical actuation instead of the electrically controlled solenoid valve 118 Modified Form of the Invention Where the Hoist is Secured Directly to the Bridge (FIG. 11)

While the description and drawings heretofore discussed have shown a crane 20 having a trolley 30, this is not necessary in order to practice the present invention, and there are cranes having movable bridges but no trolley and employing a stationary hoist. Such a structure is shown in FIG. 11, where the hoist 35 is supported directly on the bridge 21 by means of a stationary frame 230. The depending vertical members 50 and 51 are secured directly to the bridge beams 27 (or to the stationary frame 230, if desired), by a structure similar to that illustrated in FIG. 5 but not necessarily identical.

In this form of the invention, of course, the hoist 35 cannot travel back and forth on the bridge 21, but the bridge 21 can still move, as shown in FIG. 1; so the invention can be used to transport plate. The drum 36 may be supported on a couple of standards 231 that extend up from the frame member 230, while bolts 232, or other securing means, hold the frame 230 to the beams 27 of the bridge 21. Of course, the frame 230 may be welded to the bridge 21 if that is desired.

Modified Structure Having Three Legs (FIG. 12)

While the device has so far been described in connection with two depending legs 50 and 51, there may be more or fewer than two. FIG. 12 shows a structure in which three legs 240, 241, and 242 depend from the trolley 30. The stabilizer 70 is made accordingly, but is not illustrated because anyone skilled in the art knows how to provide an additional tube like the tubes 72 and 73 and how to adapt the frame 71 to join all three tubes together.

In this instance, the depending leg 240 is supported by frame members 243 and 244 that are in turn welded to the members 55, which are welded or otherwise secured to the trolley 30. Similarly, supporting members 245, 246, and 247 secure the two depending legs 241 and 242 to the members 55 of the trolley 30. Other structure may be used as desired. It will be noted that the tips 61 of the legs 24%, 241, and 242 are preferably equidistant from a center line 248 be- 2% tween the two runs of the cable 37. Operation is the same as in the preferred forms of the invention heretofore described. It will be obvious from this simple presentation that no greater difiiculty, though some additional expsnse, is presented in providing more than three legs and any design engineer can do so where it is desired for any reason.

A Modified Form of Latch Structure (FIGS. 13 and 14) In place of the latch structure shown in FIGS. 8 and 9, a modified form of latch structure may be employed. In FIGS. 13 and 14 a latch 250 comprises a large latching dog 251 pivotally secured by a pintle 252 to a projection 253 on a collar 254, which, in turn, is welded to the upper end of a stabilizer tube 73. The latch is preferably made with a sloping upper face 255 and with a latching tooth 255 at its lower end.

When the stabilizer tube 73 is raised relative to the member 51, the lower sloping portion 61 near the tip 60 engages the latching tooth 25s and swings it on its pintle 252, so that it retracts out of the way through a hole 257. it remains retracted until the stabilizer tube has been raised to the point where the tooth 256 is above the shoulder 63, and then its weight swings it in, since it is purposely made to be olf balance with respect to its pivot. Once engaged, the tooth 256 prevents any relative motion back. if the operator fails to stop the upward movement of the tube 73, the tooth 256 will simply engage the sloping face 64 and swing the latch 25% out. It automatically looks into place as did the latch 75, but there are no springs required in the latch 259, since its swinging movement and gravity are adequate. Moreover, an observer from below can tell by looking when it is engaged, for it is then horizontal (FIG. 13), as distinct from its tilted position shown in FIG. 14.

When it is desired to open the latch 260 and disconnect the stabilizer tube '73 from the leg 51, the operator simply pulls on a cord 258. The upper end of the cord 258 is attached to a lever arm 25% which is, in turn, welded, bolted, or otherwise permanently and rigidly secured to the dog 251. The pull naturally causes the latch 250 to swing on its pivot 252 and therefore to retract to the position shown in P16. 14, where it is possible to detach the stabilizer tube 73 from the depending leg 51 simply by moving it down. Of course, the same or similar structure can be used with the other leg 50 or with any other number of legs.

M'odified Form of the Invention Employing Only One Leg There need not be as many as two stabilizer legs. As shown in the structure of FIGS. 15 through 18, there may be only a single vertical depending leg 26$ with a single stabilizer member 261 and a single sliding guide member or standard 262 In this instance the frame d is secured to and forms part of a frame structure 263 having a vertical standard 264 with an opening 265 near its upper end and a rod 266 for the hook 43 to engage. The standard 262' is at one side of the standard 26dand is supported by a horizontal frame member 267. The cable 150 is secured substantially as before, and the contents sup ported by the frame 95 may also be the same as those shown in other drawings.

When using a single-leg structure, it is advisable to counterbalance the frame 263 so that the weight of the horizontal member 267 and the standard 262 do not throw the frame 95 off true balance and to assure a center of gravity extending through the vertical aXis of the standard 264 and therefore in line with the cable 37 and book 40 which do the lifting. This may be accomplished by disposing the compressor and motor on the opposite side of the frame from the standard 262, or it may be done by using a special counterbalance, or it may be done by a combination of the two. Obviously, the distance from the center line through the standard 2641s important and a weight balance can easily be achieved.

It is also important to prevent relative rotation between the standard 262 and its stabilizer 261. This may be done as shown in FIG. 16 by using a standard 26-2 of square cross section in a stabilizer tube 261 of square cross section. Or it may be done by having them rectangular or triangular or in .any other prism shape. .In this case the stabilizer and standard are still adapted so that the standard telescopes within the stabilizer. Bearing members 268 may be employed to avoiddirect contact with walls and to form substantially the .same function that the bearings 83 and 89 perform in the previously-described apparatus. Of course, this square or prismatic type of telescoping system may be used as .well in the other forms of the invention previously described, though they are not necessary where there is more than one vertical leg. Similarly, the stabilizer 261 is secured to the .leg 26%) by latch structure which may be like that of FIGS. 13 and 14 or like that in FIGS. .8 and 9, except that in this instance the sections are square or prismatic, to prevent relative rotation between the leg 26b and the stabilizer 2.61. If the leg 259 should tend to throw the trolley car 39 oil. balance, of course it is possible to add a suitable counterbalance to the car 30, but this is not usually necessary since the weight concerned is that of the dependiug leg 26% and stabilizer tube 261 and not that of the heavy frame 263 down below.

FIGS. 17 and 18 show that it is not necessary to have telescoping tubes, although they are very convenient. In any form of the invention, and particularly in this single form, other stabilizing means may be employed. Inthis instance a stabilizer member 271} and a frame standard 271 are both I-beams. The I-beams 270 and 271 supply a natural channel for two pairs .of wheels 272 and 273. Each pair 272 runs in a track 274 provided by the I-beam 270, while each of the wheels 273 runs in a track 275 provided by the l-beam 271. The wheels 272 are supported on a bracket .276 which is secured to the I-beam 271, while the wheels 273 are supported on a bracket 277 secured to the I-bearn 270. Thus, when the I-beam 270 rides up and down, the I-beam 271 will guide it and hold it vertically .and in proper alignment without the strictly telescoping action that has been previously described. Any other suitable type of stabilization that maintains the members in proper vertical alignment may be used. The operation is the same as for the other forms of the invention, with the exceptions just described.

Of course, other modifications are possible, including provision of turntables on the trolley 30 and other structure familiar in the crane art. The many examples given have been all illustrative, not with any intention of confining the invention within narrow limits, but to show a few of t e best ways in which the invention can be practiced and how it can be applied to existing equipment to achieve rapidity and safety in the operation of. moving steel plate or anything else that contact-lift means is desired to move.

Again, the safety hooks 121 need not be powered pneumatically; they may be powered hydraulically or electrically or through various kinds of power means. The pneumatic form is a good one to use and has been shown because it is presently preferred, but obviously many other things could be used if desirable under the circumstances.

To those skilled in the art to which this invention relates, many changes in construction and widely differing embodiments and applications of the invention will suggest themselves without-departing from the spirit and scope of the invention. The disclosures and the description herein are purely illustrative and are not intended to be in any sense limiting.

We claim:

1. A lifting attachment for an overhead crane having a bridge providing a pair of rails, a trolley movable on said rails, a hoist supported by said trolley and provided with cable means extending between said rails and down,

1 1 a hook on the lower end of said cable means, and control means for said hoist and trolley, said attachment including the combination of: two vertical members depending from said trolley between said rails on opposite sides of said cable and comprising a short pair of generally cylindrical members rigidly secured to said trolley and having tapered lower ends and annular recessed portions above said lower ends, a pair of long cylindrical extension tubes, and a frame cross member holding said tubes in mutual alignment, the upper ends of said tubes being adapted to receive said tapered lower ends of said cylindrical members and having radially extending locking members that are retractable to receive said lower ends and then lock in said recessed portions; and a frame supporting a plurality of contact-lifting means and means for activating them and having three-in-line vertical members extending up from said frame, a center one having means to engage said hook and two outer ones each telescopically engaging one of said extension tubes for free sliding vertical movement and acting to prevent rotation of said frame relative to said trolley, said outer ones comprising a pair of long cylindrical standards freely slidable in said tubes below said cylindrical members, the tele scopically engaging members performing no load-supporting function, the full load of said frame and the members supported thereby being carried by said cable.

2. The attachment of claim 1 wherein said recessed portions terminate in a radial shoulder at their lower end and a frusto-conical outwardly tapering portion at their upper end and said locking members are yieldingly urged radially inwardly.

3. The attachment of claim 1 wherein there are cylindrical portions of said cylindrical members above said tapered lower ends and below said recessed portions, the said cylindrical portion of one member being longer than that of the other to aid installation by making it possible to position the tapered lower end of the longer member in its tube and then moving the tube up to hold that member in and then engaging the other member in its tube.

4. A vacuum lifting attachment for an overhead crane having a bridge providing a pair of rails, a trolley movable on said rails, a hoist supported by said trolley and provided with cable means extending between said rails and down, a hook on the lower end of said cable means, and control means for said hoist and trolley, said attachment comprising a pair of generally cylindrical members rigidly secured to and depending from said trolley and having tapered lower ends and annular recessed portions above said lower ends; a pair of long cylindrical extension tubes held in mutual alignment by a frame cross member, the upper ends of said tubes being adapted to receive said tapered lower ends of said cylindrical members and having radially extending retractable locking members that look in said recessed portions; a frame supporting a plurality of contact lift means and having three in-line vertical members extending up from said frame, a center one having means to engage said hook and two outer cylindrical standards each telescopically engaging and freely slidable in one of said tubes below said cylindrical members to prevent rotation of said frame relative to said trolley, the telescopically engaging members performing no load-supporting function, the full load of said frame and members supported thereby being carried by said cable means.

5. A lifting attachment for an overhead crane having a trolley, a hoist supported by said trolley and provided with cable means, a hook on the lower end of said cable means, and control means for said hoist and trolley, said attachment comprising: a plurality of generally short cylindrical members rigidly secured to and depending from said trolley and having tapered lower ends and annular recessed portions above said lower ends, a corre sponding plurality of long cylindrical extension tubes, means for holding said tubes in mutual alignment, the

upper ends of said tubes being adapted to receive said tapered lower ends of said cylindrical members and having radially extending locking members that are retractable to receive said lower ends and then lock in said recessed portions, means operable from ground level for retracting said locking members to release the attachment between said extension tubes and said short cylindrical members and a frame supporting a plurality of contact-lifting means and means for activating them and having a plurality of vertical members extending up from said frame, one hav ing means to engage said hook and others each telescopically engaging one of said extension tubes for free sliding vertical movement and acting to prevent rotation of said frame relative to said trolley, the telescopically engaging members performing no load-supporting function, the full load of said frame and the members supported thereby being carried by said cable.

6. The attachment of claim 5 wherein said recessed portions terminate in a radial shoulder at their lower end and a frusto-conical outwardly tapering portion at their upper end and said locking members are yieldingly urged radially inwardly.

7. The attachment of claim 5 wherein there are cylindrical portions of said cylindrical members above said tapered lower ends and below said recessed portions, the said cylindrical portion of one member being longer than that of the other to aid installation by making it possible to position the tapered lower end of the longer mcmber in its tube and then moving the tube up to hold that member in and then engaging the other member in its tube.

8. A lifting attachment for an overhead crane having a trolley, a hoist supported by said trolley and provided with cable means, a hook on the lower end of said cable means, and control means for said hoist and trolley, said attachment comprising: a short rectangular member rigidly secured to and depending from said trolley and having a tapered lower end and a recessed portion above said lower end, a long rectangular extension tube, the upper ends of said tube being adapted to receive said tapered lower end of said short member and having radially extending locking means that is retractable to receive said lower end and then look in said recessed portions, means operable from ground level for retracting said locking means to release the attachment between said extension tube and said short rectangular member and a frame supporting a plurality of contact-lifting means and means for activating them and having a pair of vertical members extending up from said frame, one having means to engage said hook and the other telescopically engaging said extension tube for free sliding vertical movement while acting to prevent rotation of said frame relative to said trolley, the telescopically engaging members performing no load-supporting function, the full load of said frame and the members supported thereby being carried by said cable.

9. The attachment of claim 8 having counterbalance means for said frame for assuring a center of gravity through said hook-engaging vertical member.

10. A lifting attachment for an overhead crane having a trolley, a hoist supported by said trolley and provided with cable means extending down therefrom, a hook on the lower end of said cable means, and control means for said hoist and trolley, said attachment comprising: at least one short member rigidly secured to and depending from said trolley; a long extension member for each said member; locking means for releasably attaching the upper end of said extension member to said short member; means operable from ground level for releasing said locking means; and a frame supporting a plurality of contact-lifting means and means for activating them and having a plurality of vertical members extending up from said frame including one having means to engage said hook and one for each said extension member, engaging said extension member for free sliding vertical movement and acting to prevent rotation of said frame relative to said trolley, the telescopically engaging members performing no load-supporting function, the full load of said frame and members supported thereby being carried by said cable.

11. A lifting attachment for an overhead crane having a hoist with cable means having a hook on its lower end, said attachment comprising a frame supporting an auxiliary lifting device and having at least one vertical standard extending up from said frame and means to engage said hook; at least one short vertical member depending from said crane, rigidly secured to said crane and having a locking fitting on its lower end; an extension member adapted to engage said locking fitting in its upper end and having remotely operable latching means for detachably securing it in place, each vertical standard that extends up from the frame fitting into engagement with said extension member and being freely slidable with respect thereto, the engaging standard, vertical mem ber and extension member performing no load-supporting function, the full load of said frame and members supported thereby being carried by said cable; an overlength remote control means for said latching means extending below said extension member and operable by a man on ground level for attaching and detaching said extension member.

12. A plate-lifting attachment for an overhead crane having a hoist provided with cable means having. a hook on its lower end, and control means for said hoist, said attachment comprising first vertical means depending from said crane, and rigidly secured to said crane; extension means having an upper end adapted to be releasably locked to said lower end of said first vertical means; a frame supporting an auxiliary plate-lifting device and having second vertical means extending up from said frame and means to engage said hook, said second vertical means engaging said extension means for free sliding vertical movement and having means cooperating therewith to prevent swinging and rotation of said frame relative to said trolley, said first and second vertical means and said extension means performing -no load-supporting function, the full load of said frame and plate-lifting device being carried by said cable; and means operable from ground level to release the attachment between said first vertical means and said extension means when they are attached high above ground level.

13. A lifting attachment for an overhead crane having a trolley, a hoist supported by said trolley and provided with cable means, a hook on the lower end of said cable means, and control means for said hoist and trolley, said attachment comprising: a short support member rigidly secured to and depending from said trolley and having first locking means thereon, a long extension member having a main depending I-beam portion and first roller means projecting therefrom, the upper ends of said extension member having second locking means thereon to engage said first locking means; a frame supporting a plurality of contact-lifting means and means for activating them and having a pair of vertical members extending up from said frame, one having means to engage said hook and the other being a second I-beam with second roller means projecting therefrom, said first roller means engaging said second I-beam and said second roller means engaging said extension I-beam, for free sliding vertical movement While acting to prevent rotation of said frame relative to said trolley, said I- beams performing no load-supporting function, the full load of said frame and the members supported thereby being carried by said cable; and counterbalance means on said frame for balancing said frame and providing its center of gravity along the axis of the hook-engaging vertical member.

References Cited in the file of this patent UNITED STATES PATENTS 

